The present invention relates to a headlight for motor vehicles.
More particularly, it relates to a headlight for a motor vehicle, which has a reflector, a gas discharge lamp arranged inside the reflector, a glass cylinder surrounding the gas discharge lamp at least partially and absorbing the light in UV wavelength region, and a light stop for partial screening of the light.
Headlights of the above mentioned general type are known in the art. One of such headlights is disclosed for example in the German reference DE 40 19 587 A1. The headlight has a reflector in which a gas discharge lamp is arranged on a lamp support, the gas discharge lamp in its region extending in the reflector is surrounded at a distance by a glass cylinder formed as an encasing bulb. The encasing bulb absorbs light in the UV-wavelength range at least partially, so that no damaging UV radiation can be emitted from the headlight. The encasing bulb is mounted on the lamp support by several spring arms. Moreover, a light stop is provided in order to partially screen the light emitted by the gas discharge lamp, for avoiding blinding or glaring. The light stop is formed by a light-impermeable coating applied on the encasing bulb. Due to the receptacle for the encasing bulb, the lamp support has a complicated shape which causes manufacturing difficulties especially when it is produced of ceramics. The encasing bulb is formed as a closed element, so that an air exchange between its inner chamber in which the gas discharge lamp is arranged, and the surrounding area is not possible. As a result, very high temperatures can develop in the inner chamber.